Inhalation device for powdered medicaments

ABSTRACT

A powder dispenser 10 includes a powder housing 28 for holding a supply of powdered material to be dispensed, the powder housing including a first conduit 32 extending there through in displaced relation to the powdered material; a metering plate 16 having only a single receptacle area 24 for holding a metered amount of the powdered material above a gas-permeable powder retainer 26 mounted at the metering plate, and being positioned below the powdered material, and the metering plate and the powder housing being rotatable with respect to each other so that the receptacle area is adapted to be in selective communication with the supply of powdered material or the first conduit; a base housing 48 being mounted below the metering plate and including a second conduit 52 in alignment with the first conduit at least concurrently with alignment of the receptacle area and the first conduit; a spring 62 for biasing the base housing and the powder housing toward each other; a mouthpiece 92 for enabling inhalation of the metered amount of powdered material from the receptacle area in the metering plate through the first conduit in the container, the mouthpiece being in fluid communication with the first conduit.

INTRODUCTION TO THE INVENTION

The present invention relates generally to powder dispenser assembliesand, more particularly, is directed to a powder dispenser assembly usedfor inhalation of a metered dose of a powdered medicament.

When delivering medicaments, that is, pharmacologically activecompounds, in solid form to the respiratory tract and to the lungs,careful attention to the accuracy of the dosage, which can be as smallas 0.1 milligram, must be made. This is because such medicaments areoften quite potent, and the administration of excessive amounts thereofcould be harmful to the patient. Further, if the dosage that isdelivered is too small, it will not serve its purpose.

It is also necessary that the particles leaving the dispenser assemblybe substantially within a particular size range, since particles of themedicament which are too large may not enter the respiratory tract, butinstead, will be deposited in the mouth or pharynx and thence enter thedigestive tract. As an example, preferred particles can have a diameterof 1 to 5 micrometers.

Various devices have been used in order to dispense a metered dose ofpowdered medicament, including pressurized aerosol devices, nebulizingdevices, pump inhalators and the like. With the current concern overenvironmental issues, however, aerosol devices, which constitute a largepart of the devices now on the market, are less favored. Further, withaerosol devices, the medicament is dissolved or suspended in a liquidpropellant mixture, which results in the introduction of unneededchemical substances into the body and further adds to the complexity ofthe devices.

In addition to the aforementioned types of dispenser assemblies, powderdispenser assemblies are also known. Studies have shown that there arevirtually no significant differences in bronchodilator responses withequivalent amounts of medicinal substances administered either by powderdispensing devices or aerosol devices. Accordingly, there is now anever-growing demand for powder dispensing devices which can dispensemetered doses of powdered medicament. With such devices, the powder isdispensed during inspiration following expiration so that there is lessneed to provide a synchronized release of medication with the exactstart of inspiration to insure quality of the product delivery.

U.S. Pat. No. 4,524,769 to Wetterlin, the entire disclosure of which isincorporated herein by reference, describes a dosing unit that includesa storage chamber for holding the active compound, a perforated membranerotatably positioned under the storage chamber and a holder for themembrane. Introduction of the active compound into perforations in theperforated membrane is accomplished with elastic, spring-loadedscrapers, mounted in a holder in the storage chamber. With thisarrangement, the membrane is movable between a first position whereactive compound is introduced by the scrapers in part of the area of theperforated membrane, and a second position where the part of the area ofthe loaded membrane has been inserted into the air conduit in the dosageinhalator. Thus, the active compound contained in the perforations isentrained at inhalation and brought through the nozzle to therespiratory tract and the lungs of the patient.

With this arrangement, a coil spring is used to bias the scrapers intoengagement with the perforated membrane. The coil spring is interposedin the storage chamber between the casing and the scraper assembly.Alternatively, it is disclosed that the coil spring can be arranged sothat the membrane is pressed against the scrapers, and thereby mountedin the base or maneuvering unit. In addition to the coil spring,Wetterlin uses spring loaded pins beneath the membrane to engage theratcheted bottom of the membrane in order to provide distinct positionsfor the perforated membrane when it is advanced by the base ormaneuvering unit. This, of course, further complicates the constructionand assembly of the device. See also U.S. Pat. Nos. 4,907,583;4,534,345; and 4,667,668; all to Wetterlin.

U.S. Pat. No. 4,805,811 to Wetterlin discloses a dosage device which issubstantially identical in all relevant respects to U.S. Pat. No.4,524,769 to Wetterlin. With the '811 Wetterlin Patent, there is anadditional funnel-like feed element positioned above the scraping unit.Also, the dosing member is provided with five recesses which aredifferent from those described in the '769 Patent. Further, there is aspring which biases from below, unlike the '769 Patent, and the lockingmechanism of the powder housing to the base housing or operating memberis somewhat different.

However, with these minor differences aside, the same deficiencies foundin Wetterlin '769 are found in Wetterlin '811. Thus, the devices of theWetterlin patents all provide a relatively complicated and costlyarrangement. This is the result of providing a plurality of openings ina metering plate which must be rotated separately from the main housing.Further, by providing a plurality of openings in the metering plate, arelatively complicated indexing mechanism must be provided, which issubject to breakage and which is difficult to assemble. Specifically,the Wetterlin patents require a ratchet mechanism to perform suchindexing.

U.S. Pat. No. 4,668,218 to Virtanen discloses a dispenser substantiallyidentical to the Wetterlin patents, while also providing an indicatingassembly which indicates the number of medicament dosages administered.

SUMMARY OF THE INVENTION

In accordance with an aspect of the present invention, a powderdispenser includes powder housing means for holding a supply of powderedmaterial to be dispensed, the powder housing means including a firstconduit extending there through in displaced relation to the supply ofpowdered material; metering plate means for holding a metered amount ofthe powdered material, the metering plate means including only a singlepowder receptacle area therein for holding the metered amount of thepowdered material, the metering plate means being positioned below thesupply of powdered material, and the metering plate means and the powderhousing means being rotatable with respect to each other so that thereceptacle is adapted to be in fluid communication selectively with thesupply of powdered material or the first conduit; base housing means forpreventing air flow through the receptacle except when the receptacle isin alignment with the first conduit of the powder housing means, thebase housing means being mounted below the metering plate means, and thebase housing means including a second conduit in alignment with thefirst conduit of the powder housing means when the receptacle is inalignment with the first conduit of the powder housing means; springmeans for biasing the base housing means and the powder housing meanstoward each other; and mouthpiece means for enabling inhalation of themetered amount of powdered material from the receptacle in the meteringplate means through the first conduit in the container means, themouthpiece means being in fluid communication with the first conduit.

In accordance with another aspect of the present invention, a powderdispenser further includes rotational drive means for rotating thepowder housing means with respect to the metering disk means so that thefirst conduit is in fluid communication with the receptacle, inassociation with movement of the mouthpiece means to an exposed positionto enable inhalation therefrom.

The above and other features of the invention will become readilyapparent from the following detailed description thereof which is to beread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a metered powder dosedispenser according to a first embodiment of the present invention;

FIG. 2 is a longitudinal cross-sectional view of the metered powder dosedispenser of FIG. 1 in assembled form;

FIGS. 3A and 3B are cross-sectional views of the metered powder dosedispenser of FIG. 2, taken along line 3-3 thereof;

FIG. 4 is a bottom perspective view of the powder housing of the meteredpowder dose dispenser of FIG. 1;

FIG. 5 is an exploded perspective view of a metered powder dosedispenser according to a second embodiment of the present invention;

FIGS. 6A and 6B are top plan views of the assembled stationary body andcap holder of the metered powder dose dispenser of FIG. 5;

FIG. 7 is a side elevational view of the assembled stationary body andcap holder of the metered powder dose dispenser of FIG. 5;

FIG. 8 is a top plan view of the base housing of the metered powder dosedispenser of FIG. 5;

FIG. 9 is a plan view of the scraper plate of the metered powder dosedispenser of FIG. 5;

FIG. 10 is a top plan view of the assembled stationary body, cap holderand powder housing;

FIG. 11 is a longitudinal cross-sectional view of the metered powderdose dispenser of FIG. 10, with the cap thereon, taken along line 11--11thereof:;

FIG. 12 is an enlarged longitudinal cross-sectional view, similar toFIG. 11, of the upper portion of the stationary body, cap holder andpowder housing;

FIG. 13 is a bottom plan view of the cap of the metered powder dosedispenser of FIG. 5;

FIG. 14 is a cross-sectional view of the cap of FIG. 12, taken alongline 13--13 thereof;

FIG. 15 is a front elevational view of the mouthpiece of the meteredpowder dose dispenser of FIG. 5;

FIG. 16 is a top plan view of the mouthpiece of FIG. 15;

FIG. 17 is a cross-sectional view of the mouthpiece of FIG. 15, takenalong line 17--17 thereof;

FIG. 18 is a top plan view of the key disk of the driver mechanism ofthe metered powder dose dispenser of FIG. 5;

FIG. 19 is a cross-sectional view of the key disk of FIG. 18, takenalong line 19--19 thereof;

FIG. 20 is a cross:sectional view of the assembled cap, cap holder,mouthpiece and key disk of the metered powder dose dispenser of FIG. 10,taken along line 20--20 thereof;

FIG. 21 is a cross-sectional view similar to FIG. 20, with themouthpiece extended out of the window of the cap;

FIG. 22 is an exploded perspective view of a metered powder dosedispenser according to a third embodiment of the present invention;

FIG. 23 is a perspective view of the assembled metered powder dosedispenser of FIG. 22 in the closed position, with the cap removed;

FIG. 24 is a longitudinal cross-sectional view of the metered powderdose dispenser of FIG. 23;

FIG. 25 is a top plain view of the base housing of the metered powderdose dispenser of FIG. 22;

FIG. 26 is a cross-sectional view of the base housing of FIG. 25, takenalong line 26--26 thereof;

FIGS. 27A and 27B are top plan views of the metering disk portion of themetered powder dose dispenser of FIG. 22;

FIG. 28 is a cross-sectional view of the metering disk portion of FIG.27, taken along line 28--28 thereof;

FIG. 29 is a bottom plan view of the powder housing of the meteredpowder dose dispenser of FIG. 22;

FIG. 30 is a cross-sectional view of the powder housing of FIG. 29,taken along line 30--30 thereof;

FIG. 31 is a top plan view of the scraper disk of the metered powderdose dispenser of FIG. 22;

FIG. 32 is a cross-sectional view of the scraper disk of FIG. 33, takenalong line 32--32 thereof;

FIG. 33 is a perspective view of the assembled base housing and meteringdisk portion of the metered powder dose dispenser of FIG. 22;

FIG. 34 is a perspective view of the assembled base housing and meteringdisk portion of FIG. 33, with the metering disk portion rotated 180°with respect to the base housing from the position shown in FIG. 33;

FIG. 35 is an elevational view of the assembled base housing, meteringdisk portion, scraper plate, powder housing and nozzle;

FIG. 36 is an elevational view of the assembled base housing, meteringdisk portion, scraper plate, powder housing and nozzle, viewed from aposition 90° offset from the position of FIG. 35;

FIG. 37 is an elevational view of the assembled base housing, meteringdisk portion, scraper plate, powder housing and nozzle, viewed from aposition 180° offset from the position of FIG. 35;

FIG. 38 is a top plan view of the nozzle of the metered powder dosedispenser of FIG. 22;

FIG. 39 is a cross-sectional view of the nozzle of FIG. 38, taken alongline 39--39 thereof;

FIG. 40 is an elevational view of the guide sleeve of the metered powderdose dispenser of FIG. 22;

FIG. 41 is an elevational view of the guide sleeve of FIG. 40, viewedfrom a position 90° offset from the position of FIG. 40;

FIG. 42 is an elevational view of the guide sleeve of FIG. 40, viewedfrom a position 180° offset from the position of FIG. 40;

FIG. 43 is a top plan view of the guide sleeve of FIG. 40;

FIG. 44 is a bottom plan view of the driving sleeve of the meteredpowder dose dispenser of FIG. 22;

FIG. 45 is a cross-sectional view of the driving sleeve of FIG. 44,taken along line 45-45 thereof;

FIG. 46 is a perspective view of the assembled metered powder dosedispenser of FIG. 22, with the cap removed and without the bottomfriction cap and top friction sleeve, and in the retracted position;

FIG. 47 is a perspective view of the assembled metered powder dosedispenser of FIG. 46, in the extended, operable position;

FIG. 48 is a cross-sectional view of a metered powder dose dispenseraccording to a fourth embodiment of the present invention;

FIG. 49 is an exploded perspective view of a metered powder dosedispenser according to a fifth embodiment of the invention;

FIG. 50 is a cross-sectional view of the assembled dispenser of FIG. 49;and

FIG. 51 is a top view of the partially assembled powder dispenser ofFIG. 49.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the drawings in detail, and initially to FIGS. 1-4 thereof,a metered powder dose dispenser 10 according to a first embodiment ofthe present invention includes a stationary body 12 formed by acylindrical wall 14 that is divided into an upper half cylindrical wallportion 14a and a lower half cylindrical wall portion 14b by a meteringdisk portion 16 integrally formed with cylindrical wall 14. Therefore,as shown in FIG. 2, stationary body 12 has a substantiallyH-configuration in the longitudinal cross-section thereof, with an uppercup-shaped recess 18 being formed between upper half cylindrical wallportion 14a and disk portion 16, and a lower cup-shaped recess 20 beingformed between lower cylindrical wall portion 14b and disk portion 16.

Disk portion 16 is formed with a central opening 22, and a single powderreceptacle 24 (FIG. 3A) is located near the periphery thereof.Receptacle 24 is above a gas-permeable powder retainer 26. Receptacle 24and retainer 26 can be formed by inserting a gas permeable filter, meshor perforated plate element, having a height less than the thickness ofmetering disk 16, into the lower portion of an opening of suitabledimension and shape in said metering disk; receptacle 24 will thus beformed above the element in the opening. Alternatively, powderreceptacle 24 can comprise an opening in disk 16 and powder retainer 26can comprise a covering on the lower surface of said disk, extending atleast over said opening. As a further alternative, metering disk 16 isformed from a porous material and powder receptacle 24 is formed by arecess in the disk. The filter, mesh or plate element constitutesretainer 26, and preferably has a minimal restrictive effect on gas flowtherethrough, while preventing appreciable loss of powdered medicamentbelow the lower surface of metering disk 16. To maintain a constantvolume of powder receptacle 24, powder retainer 26 is preferably fixedlymounted in or below the opening, such as by frictional fit, welding oruse of an adhesive. A gas permeable filter, mesh or plate can befabricated from any suitable material, including cellulosics,polymerics, metals, ceramics, glasses or composites thereof, exemplaryuseful materials including sintered porous plastics, porous polymermembranes, natural or synthetic woven fabrics, nonwoven syntheticfabrics and the like. More specifically, useful materials includepolyester and polyolefin woven mesh, and porous membranes ofpolyolefins, polycarbonates, poly-tetrafluoroethylene, polyvinylidenedichloride, and mixed esters of cellulose.

Alternatively, as shown in FIG. 3B, receptacle 24 comprises an area ondisk portion 16, wherein powder is introduced into perforations 25,sized such that the powder will be retained therein until inhaled by theuser. No retainer will typically be used with this configuration.

A powder housing 28 of a cylindrical configuration is positioned withinupper cup-shaped recess 18. Powder housing 28 sits upon the uppersurface of disk portion 16 and has an outer diameter smaller than theinner diameter of cylindrical wall 14 so as to permit relative rotationbetween powder housing 28 and stationary body 12. Powder housing 28includes a central threaded opening 30 in line with central opening 22of disk portion 16. In addition, powder housing 28 includes a firstfrusto-conical venturi conduit 32 extending entirely there through,substantially parallel to and offset from the central axis thereof so asto be positioned at the periphery of powder housing 28. Venturi conduit32 has its large diameter end 32a at the upper end of powder housing 28,and its small diameter end 32b adjacent disk portion 16. In this manner,small diameter end 32b of venturi conduit 32 can be aligned withreceptacle 24 to receive powdered medicaments 34 therefrom. As usedherein, the terms "powdered medicaments" and "powder" include micronizedpowder, spheronized powder, micro-encapsulated powder, powderagglomerates and the like, and are used interchangeably with these termsherein.

In addition, powder housing 28 includes a powder supply conduit 36positioned diametrically opposite venturi conduit 32, with the lower endof powder supply conduit 36 capable of being aligned with receptacle 24,as shown in FIG. 2. Powder supply conduit 36 is normally filled withpowder 34 for inhalation, and the upper end of powder supply conduit 36is closed by a plug 40 or the like to prevent the escape of powder fromthe upper end of powder supply conduit 36.

The lower end of powder supply conduit 36 exits into a manifold 42formed in the lower surface of powder housing 28. Manifold 42 extendsalong an arcuate path of powder housing 28 at the periphery thereof, andis divided into chambers 44 by scraper plates 46. The upper end of atleast one chamber 44 is in communication with the lower end of powdersupply conduit 36, while the lower ends of all chambers are adapted tobe in communication with receptacle 24 upon relative rotation betweenpowder housing 28 and disk portion 16. Further, the lower ends ofscraper plates 46 are at the same level as the lower surface of powderhousing 28, and therefore, are in contact with the upper surface of diskportion 16. Accordingly, upon relative rotation between stationary body12 and powder housing 28, powder 34 falls into at least one chamber 44of manifold 42 from powder supply conduit 36, and then is scraped byscraper plates 46 into receptacle 24 so as to accurately and completelyfill the same.

Metered powder dose dispenser 10 further includes a base housing 48 of acylindrical configuration, positioned within lower cup-shaped recess 20.Base housing 48 also has an outer diameter smaller than the innerdiameter of cylindrical wall 14 so as to permit relative rotationbetween base housing 48 and stationary body 12. Further, base housing 48includes a central opening 50 in line with central opening 22 of diskportion 16. A second frusto-conical venturi conduit 52 extends entirelythrough base housing 48, substantially parallel to and offset from thecentral axis thereof, so as to be positioned at the periphery of basehousing 48. Venturi conduit 52 has its large diameter end 52a at thelower end of base housing 48, and its small diameter end 52b adjacentdisk portion 16. In this manner, small diameter end 52b of venturiconduit 52 can be aligned with receptacle 24, and therefore, in linewith powder 34 therein. As will be described hereinafter in greaterdetail, base housing 48 is rotatably fixed with respect to powderhousing 28 so that second venturi conduit 52 is always in alignment withfirst venturi conduit 32.

As shown best in FIGS. 1 and 2, base housing 48 includes an annularL-shaped lip 54 at the lower end thereof. Lip 54 defines an annulargroove 56 for seating the lower end of cylindrical wall 14 therein.

Further, a central recess 57 is formed at the lower end of base housing48, recess 57 being in fluid communication with central opening 50.

In order to rotatably lock base housing 48 to powder housing 28, a bolt58 is inserted through central recess 57, central opening 50 and centralopening 22, and threadedly received in central threaded opening 30 ofpowder housing 28. A conventional key-way arrangement 60 is provided inconnection with central opening 50 of base housing 48 and on bolt 58 toprevent relative rotation between base housing 48 and bolt 58. As aresult, relative rotation between powder housing 28 and base housing 48is prevented, while permitting axial sliding movement there between. Inother words, rotation of base housing 48 results in rotation of powderhousing 28 therewith. However, base housing 48 and powder housing 28 canbe moved toward and away from each other in the axial directionsthereof.

It is important to the present invention that powder 34 not prematurelyescape from receptacle 24, and in this regard, a coil spring 62 ispositioned in central recess 57 between base housing 48 and the head 58aof bolt 58 in order to normally bias powder housing 28 and base housing48 together in the axial directions thereof. As a result, the lowersurface of powder housing 28 is in contact with the upper surface ofdisk portion 16, while the upper surface of base housing 48 is incontact with the lower surface of disk portion 16. In this manner, theescape of powder 34 deposited into receptacle 24 is prevented.

In addition, the large diameter end of a frusto-conical mouthpiece 92 isfixedly mounted to the upper end of powder housing 28. An opening 93 isprovided in the opposite, small diameter end of mouthpiece 92.

In operation, venturi conduits 32 and 52 are initially in alignment withreceptacle 24. Then, stationary body 12 and base housing 48 am rotated180° with respect to each other to the position shown in FIG. 1. Duringsuch rotation, manifold 42 comes into communication with receptacle 24.As a result, powder 34 in chambers 44 therein is deposited in receptacle24 and scraped thereinto by scraper plates 46. Then, with receptacle 24filled, base housing 48 and stationary body 12 are rotated back 180°with respect to each other so that venturi conduits 32 and 52 are onceagain in alignment with receptacle 24. It is then only necessary for theuser to inhale through opening 93 in mouthpiece 92 so that air is drawnupwardly through venturi conduit 52 and powder retainer 26, therebycarrying the powder from receptacle 24 through venturi conduit 32 andout through opening 93.

It will be appreciated that scraper plates 46 of the present inventionoperate to provide the scraping action during both. counterclockwise andclockwise rotation that is both during the 180° loading stage and thereverse 180° movement to the inhalation stage.

Accordingly, with the present invention, a metered powder dose dispenser10 is provided that accurately measures the doses of powdered medicamentto be delivered to the patient. Specifically, dispenser 10 is greatlysimplified in construction and assembly over the prior art. This occursby reason of the metering disk portion being integrally formed with thestationary body that rotatably holds the powder housing and basehousing. Further, with the present invention, there is only a singlereceptacle in the metering disk portion, so as to eliminate the need forany complex ratchet assembly.

Thus, the present invention differs from the aforementioned Wetterlinpatents which require a plurality of openings in a metering plate whichmust be rotated separately from the main housing. By providing aplurality of openings in the metering plate, a relatively complicatedindexing mechanism must be provided, which is subject to breakage andwhich is difficult to assemble. Specifically, the Wetterlin patentsrequire a ratchet mechanism to perform such indexing.

Referring now to FIGS. 5-21, a metered powder dose dispenser 110according to a second embodiment of the present invention will now bedescribed, in which elements corresponding to those of dispenser 10 ofthe first embodiment are denoted by the same reference numeralsincremented by 100, and a detailed description of the common elementswill be omitted herein for the sake of brevity.

Specifically, as shown therein, the basic mechanism of dispenser 10 isfound in dispenser 110, with some variations thereof. First, instead ofa bolt 58 extending into threaded engagement directly with the main bodyof the power housing, powder housing 128 includes a central extensionshaft 128a integrally formed at the lower surface thereof. Shaft 128aextends through central opening 150 of base housing 148, into centralrecess 157. The free end of shaft 128a includes external threads 128bthereon and a nut 158 is threadedly engaged therewith, in order tosecure powder housing 128 to base housing 148. Of course, as withdispenser 10, a coil spring 162 is positioned between base housing 148and nut 158 in order to normally bias powder housing 128 and basehousing 148 together in the axial directions thereof. In this regard, awasher 158a is interposed around shaft 128a, between nut 158 and coilspring 162. As a result, the lower surface of powder housing 128 is incontact with the upper surface of disk portion 116, while the uppersurface of base housing 148 is in contact with the lower surface of diskportion 116.

Further, a key-way arrangement 160 is provided to prevent relativerotation between powder housing 128 and base housing 148, whilepermitting axial sliding movement there between. Specifically, key-wayarrangement 160 includes a small diameter stop rod 166 secured in anopening 168 at the lower surface of powder housing 128 and extendingdownwardly therefrom in the axial direction of powder housing 128. Asmall diameter opening 70 is provided in the upper surface of basehousing 148 and extends in the axial direction of base housing 148.Opening 170 is aligned with opening 168 so as to slidably receive stoprod 166 therein. As a result, rotation of powder housing 128 results inrotation of base housing 148 therewith. However, base housing 148 andpowder housing 128 can be moved toward and away from each other in theaxial directions thereof, because stop rod 166 can slide in the axialdirection thereof within opening 170.

It will be appreciated that central opening 122 of disk portion 116 isof a sufficiently large diameter to receive stop rod 166 therein. Inthis manner, rotation of powder housing 128 and base housing 148 canoccur with respect to disk portion 116, without interference from stoprod 166.

As another modification, manifold 142 is merely formed as an arcuateopen area in communication with powder supply conduit 136. In otherwords, there are no scraper plates formed in manifold 142. Instead, aseparate scraper disk 172 of identical outer diameter to powder housing128, is effectively secured to the lower surface of powder housing 128by any suitable means. For example, the central opening 174 of scraperdisk 172 can be of a slightly smaller diameter than shaft 128a so thatscraper disk 172 is force fit thereon. Alternatively, an adhesive or thelike can be used to secure scraper disk 172 to the Tower surface ofpowder housing 128. Of course, scraper disk 172 includes a smalldiameter opening 176 for receiving stop rod 166 there through, so thatscraper disk 172 is fixed in position with respect to powder housing128.

Scraper disk 172 includes a plurality of circular holes 178 extendingthere through and positioned immediately under manifold 142. It will beappreciated from the discussion that follows that holes 178 need not becircular. With this arrangement, powder 134 from powder supply conduit136 falls into manifold 142, and then into holes 178. When powderreceptacle 124 (FIG. 6A) is positioned under holes 178, powder 134therein falls into receptacle 124, above retainer 126, and is scrapedthereinto by the walls 172a of scraper disk 172 that define holes 178,during relative rotation of powder housing 128 and scraper disk 172 withrespect to disk portion 116. In Other words, these walls 172a functionin an equivalent manner to scraper plates 46 of dispenser 10.Preferably, as shown, there are four holes 178 in alignment withmanifold 142.

As shown in FIG. 6B, powder receptacle 124 can be an area comprisingperforations 125. In this modification, retainer 126 may not be neededfor retaining powder in the receptacle until inhalation is commenced.

In addition, there is an additional hole 180 in scraper plate 172 whichis in alignment with venturi conduits 132 and 152. With thisarrangement, it will be appreciated that one hole 178a is indiametrically opposite relation to hole 180. This is because manifold142 extends past powder supply conduit 136. However, it will beappreciated that venturi conduit 132 is not diametrically oppositepowder supply conduit 136, but rather, is arcuately spaced therefrom byabout a 135° arc.

Further, annular L-shaped lip 54 is eliminated with dispenser 110.Accordingly, base housing 148 fits entirely within lower cup-shapedrecess 120 of stationary body 12. In order to rotate powder housing 128and base housing 148 relative to disk portion 116, powder housing 128,rather than base housing 148, is rotated by means of a diametricaldriver slot 182 in the upper surface of powder housing 128, as will bedescribed in more detail hereinafter.

A cap holder 184 is mounted in surrounding relation to upper halfcylindrical wall portion 114a of stationary body 112 for holding a cap164 of a conventional nature thereon. For example, the arrangement ofcap 164 and cap holder 184 can be of the type sold by Somova S.p.A. ofMilano, Italy.

Specifically, stationary body 112 has an outer sleeve 115 that surroundslower half cylindrical wall portion 114b and approximately one-half ofupper half cylindrical wall portion 114a, and is secured thereto bywelding, an adhesive, a press fit or the like. The outer surface ofupper half cylindrical wall portion 114a that extends above sleeve 115,is provided on the outer surface thereof with a circumferential tang117.

Cap holder 184 includes a cylindrical gripping section 186 which isengaged over upper half cylindrical wall portion 114a and which seats onthe upper edge of sleeve 115. In this regard, cylindrical grippingsection 186 has an annular groove 186a in the inner wall thereof, whichrides over and is engaged by circumferential tang 117 to retain capholder 184 on stationary body 112. The lower edge of cylindricalgripping section 186 seats on the upper edge of sleeve 115 in order toposition tang 117 correctly with respect to annular groove 186a. Inaddition, the inner diameter of gripping section 186 is slightly smallerthan the outer diameter of upper half cylindrical wall portion 114a soas to retain gripping section 186 thereon with a friction fit. In thismanner, cap holder 184 is generally not rotatably mounted on stationarybody 112. Alternatively, a weld or an adhesive can be used.

Cylindrical gripping section 186 leads into a reduced diametercylindrical cap securing section 188 integrally formed therewith anddefining an annular shoulder 188a therewith. Cap securing section 188 isfurther formed with an annular tang 188b on the outer surface thereof soas to define an annular groove 188c between annular tang 188b andshoulder 188a, the purpose for which will be explained hereinafter.

Finally, cap securing section 188 leads into a substantiallysemi-cylindrical cap guiding section 190 integrally formed therewith andof the same diameter. One edge of cap guiding section 190 is formed witha pivot pin 190a for pivoting a mouthpiece 192 thereon, as will also beexplained hereinafter. Two recesses 190b are formed at opposite ends onthe upper edge of cap guiding section 190.

A cap 164 having a cylindrical outer wall 164a and a closed top wall164b, has its lower open end rotatably mounted to cap holder 184, whichin turn, as aforementioned, is fixed to the upper end of stationary body112. The inner diameter of cylindrical outer wall 164a is similar to theouter diameter of cap securing section 188 and cap guiding section 190.Further, the inner: surface of cylindrical outer wall 164a at the lowerend thereof, is formed with an annular groove 164c which receivesannular tang 188b to rotatably secure cap 164 onto cap holder 184. Insuch position, the lower open end of cylindrical outer wall 164a seatson annular shoulder 188a.

In addition, a window 164d is cut out of cylindrical outer wall 164a,through which the aforementioned mouthpiece 192 can extend, as will bedescribed hereinafter.

Window 164d can extend, for example, about an arc of approximately 80° .

Further, a short stop pin 164e is formed at a peripheral portion of theinner surface of top wall 164b, the purpose for which will be describedhereinafter.

Cap 164 also includes a circular peripheral groove 164h in the innersurface of top wall 164b, immediately adjacent the juncture of top wall164b with cylindrical outer wall 164a. As shown in FIG. 11, groove 164hreceives the upper edge of cap guiding section 190 therein when cap 164is assembled on cap holder 184. Two closely spaced ridges 164i and 164jare formed in groove 164h so as to receive recesses 190b on cap guidingsection 190 at the extreme rotatable positions of cap 164 in order toreleasably lock cap 164 at those positions.

A mouthpiece 192 is positioned within cap 164 and is pivotally connectedon pivot pin 190a of cap guiding section 190. As shown, mouthpiece 192is formed by two substantially parallel top and bottom walls 192a and192b, and two side walls 192c and 192d which connect together top andbottom walls 192a and 192b, and which slightly converge toward eachother at the forward ends thereof. Further, the rear portions of top andbottom walls 192a and 192b are formed with arcuate cut-outs 192e and192f, respectively. This is because top wall 164b has central shaft 164fextending down therefrom, so that it is necessary to provide cut-outs192e and 192f in order to pivot mouthpiece 192 about shaft 164f, betweenits retracted position totally within cap 164 (FIG. 20) and its extendedposition out through window 164d (FIG. 21 ). Shaft 164f has aninternally threaded opening 164g at its lower end.

In order to pivotally connect mouthpiece 192 within cap 164, mouthpiece192 is formed with a cylindrical pivot pin holder 192g connected acrossthe rear edge of side wall 192c, near the upper end thereof. Thus, pivotpin holder 192g receives pivot pin 190a in order to pivotally mountmouthpiece 192 on pivot pin 190a within cap 164.

As will be appreciated from the discussion which follows, when manifold142 is in communication with powder receptacle 124, mouthpiece 192 ispivoted to a retracted position within cap 164, and when venturiconduits 132 and 152 are in communication with powder receptacle 124,mouthpiece 192 is pivoted to an extended position out of window 164d. Inthe extended position, the user can inhale through mouthpiece 192 toreceive the medicament powder 134 held in receptacle 124.

In many instances, however, the user will feel a need to exhale intomouthpiece 192 immediately after inhaling powder 134. In other words,the user may exhale before removing his mouth from mouthpiece 192.Accordingly, moisture from the user's mouth would be supplied back toreceptacle 124. In order to prevent this occurrence, a flap 192h ispivotally mounted at its upper end by a pivot rod 192i, withinmouthpiece 192. Specifically, pivot rod 192i extends across the upperends of side walls 192c and 192d, approximately mid-way along the lengththereof, in order to pivotally mount flap 192h therein. A stop 192j isfixed to bottom wall 192b behind flap 192h in order to prevent pivotingof flap 192h rearwardly and inwardly, while permitting pivoting of flap192h outwardly. In this manner, when the user inhales, flap 192h pivotsoutwardly and upwardly to permit passage of the micronized powder 134,as shown by the dashed lines in FIG. 17. Once the user stops inhaling,flap 192h falls by gravity back to its blocking position with respect tothe opening through mouthpiece 192. If the user exhales while his mouthis still on mouthpiece 192, flap 192h is prevented from further pivotinginwardly by stop 192j. As a result, no moisture from such exhalationreaches receptacle 124.

Unlike dispenser 10 in which base housing 128 is rotated relative todisk portion 16, powder housing 128 and base housing 148 of dispenser110 are rotated relative to disk portion 116 by rotating powder housing128. This is accomplished by rotating cap 164 relative to stationarybody 112.

Specifically, rotation means 194 is mounted to cap 164 for rotatingpowder housing 128. Rotation means 194 includes a key disk 194a having acentral hole 194b and a diametrical driving key 194c at the lower endthereof. A central cylindrical boss 194f can also be provided on theopposite surface of key disk 194a. A bolt 194d extends through hole 194band the aligned boss 194f, and is threadedly engaged within internallythreaded opening 164g of shaft 164f, in order to secure key disk 194a tocap 164. Of course, other means of securing key disk 194a to cap shaft164f can be provided, such as a press fit, weld or the like. It will beappreciated, as shown, that key disk 194a, when secured to cap 164, ispositioned below the lower surface of bottom wall 192b of mouthpiece192. In order to accurately position key disk 194a, a spacer 194e can beprovided between key disk 194a and the lower end of shaft 164f. In thisposition, key disk 194a is fixed in position to cap 164. Thus, drivingkey 194c engages within diametrical driver slot 182 in the upper surfaceof powder housing 128 when key disk 194a is assembled with cap 164.Accordingly, when cap 164 is rotated on cap holder 184, driving key 194cof key disk 194a, which is engaged within driver slot 182, causesrotation of powder housing 128 therewith. Since stationary body 112 isheld stationary by the user, this results in relative rotation of powderhousing 128 and base housing 148 relative to stationary body 112. Inaddition, key disk 194a is provided with a peripheral cut-out 194g whichaligns with the upper end of venturi tube 132 when driving key 194c isengaged within driver slot 182. In this manner, when venturi tube 132 isin alignment with powder openings 126, key disk 194a will not block thepassage of powder from venturi tube 132 to mouthpiece 192.

In addition, it will be appreciated that a central bore 183 is formed inthe upper surface of powder housing 128 so as to receive the head ofbolt 194d when driving key 194c of key disk 194a is engaged withindriver slot 182.

In general operation of mouthpiece 192, when hole 178a and manifold 142are in alignment with powder receptacle 124, mouthpiece 192 ispositioned entirely within cap 164. In such position, the rear edge oftop wall 192aat the juncture with pivot pin holder 192g, is in contactwith stop pin 164e of cap 164. This prevents further rotation of cap 164on cap holder 184. In this position, it will be appreciated thatsemi-cylindrical cap guiding section 190 covers window 164d to preventaccess to mouthpiece 192 during non-use.

As cap 164 is rotated, powder housing 128 is also rotated therewith. Asa result, walls 172a scrape powder 134 into receptacle 124. After 180°of travel of powder housing 128 and base housing 148 relative to diskportion 116, venturi conduits 132 and 152, and hole 180, are inalignment with receptacle 124. During this rotation, side wall 192c hitsagainst an edge defining window 164d. Upon continued rotation of cap 164toward the position where venturi conduits 132 and 152 are in alignmentwith receptacle 124, this edge of window 164d, which is stationary,forces mouthpiece 192 out of window 164d, that is, to the only placethat mouthpiece 192 can move while permitting continued rotation of cap164. Mouthpiece 192 therefore pivots outwardly about pivot pin 190a.Because the rear edges of side walls 192c and 192d are spaced apart agreater distance than the width of window 164d, mouthpiece 192 can onlyextend out of window 164d a predetermined amount, which limits therotation of cap 164 to a fixed position. This fixed position correspondsto the alignment of venturi conduits 132 and 152, and hole 180, withreceptacle 124. The user then merely inhales through mouthpiece 192 toreceive powder 134 contained within receptacle 124.

In addition to the aforementioned advantages achieved with dispenser 10,it will be appreciated that dispenser 110 provides additionaladvantages. Specifically, the mechanism for rotating the powder housingrelative to the metering disk is associated with movement of themouthpiece between its retracted and exposed positions, and thereforeprovides a dual function in a simplified manner. Also, because of flap192h, moisture from exhalation is prevented from entering throughmouthpiece 192.

Referring now to FIGS. 22-47, a metered powder dose dispenser 210according to a third embodiment of the present invention will now bedescribed, in which elements corresponding to those of dispenser 110 ofthe second embodiment are denoted by the same reference numeralsincremented by 100, and a detailed description of the common elementswill be omitted herein for the sake of brevity.

Specifically, as shown therein, the basic mechanism of dispenser 110 isfound in dispenser 210, with some variations thereof. In particular, thearrangement of powder housing 228, base housing 248, disk portion 216and scraper plate 272 is virtually unchanged from the correspondingcounterparts in dispenser 110, with the following exceptions.

In the first place, there is only an upper half cylindrical wall portion214a to stationary body 212, so that upper half cylindrical wall portion214a and disk portion 216 effectively have a cup-shaped configurationwhich defines an upper cup-shaped recess 218 that receives powderhousing 228 therein. In place of the lower half cylindrical wallportion, there is provided a semi-cylindrical flange 214b of a smallheight, with flange 214b being formed as an extension of upper halfcylindrical wall portion 214a on the opposite side of disk portion 216.Because flange 214b has a semi-cylindrical configuration, flange 214bthereby includes two opposite stop edges 214c and 214d which function tolimit rotation of powder housing 228 and base housing 248 with respectto disk portion 216, as will be described in greater detail hereinafter.

The upper end of base housing 248 is cut-away to form a reduced diametercylindrical upper end 248a that defines an annular shoulder 248b uponwhich the lower end of flange 214b sits. An axially oriented stop pin248c is fixed within the periphery of base housing 248, and thereby doesnot increase the outer diameter thereof. Stop pin 248c extends upwardlyin the axial direction of base housing 248, and is exposed immediatelyabove annular shoulder 248b. As a result, in the assembled condition,stop pin 248c extends between stop edges 214c and 214d of flange 214b.During operation, when powder housing 228 and base housing 248 arerotated relative to stationary body 212, stop pin 248c will hit againsteither stop edge 214c or stop edge 214d to limit rotation of powderhousing 228 to 180° . These extreme positions of rotation willcorrespond to a first position in which venturi conduits 232 and 252,and hole 280, are in alignment with powder receptacle 224, above powderretainer 226, and a second position in which powder supply conduit 236,manifold 242 and holes 278 are in alignment with receptacle 224.

As with the other dispenser, configurations shown herein, powderreceptacle 224 can comprise an opening (FIG. 27A) having powder retainer226 beneath, or can comprise an area containing perforations 225 (FIG.27B).

Unlike dispenser 110, powder housing 228 and base housing 248 ofdispenser 210 are connected together in a similar manner to dispenser 10of the first embodiment. Specifically, in order to rotatably lock basehousing 248 to powder housing 228, a bolt 258 is inserted throughcentral recess 257 and central opening 250 of base housing 248, centralopening 222 of metering disk portion 216 and central opening 274 ofscraper disk 272, and threadedly received in central threaded opening230 of powder housing 228. Further, a coil spring 262 is positioned incentral recess 257 between base housing 248 and the head 258a of bolt258 in order to normally bias powder housing 228 and base housing 248together in the axial directions thereof. As a result, the lower surfaceof scraper disk 272, which is positioned below powder housing 228, is incontact with the upper surface of disk portion 216, while the uppersurface of base housing 248 is in contact with the lower surface of diskportion 216.

There is also a similar key-way arrangement 260 to that of dispenser110, with a stop rod 266, opening 268 in powder housing 228, and a smalldiameter opening 270 in base housing 248.

In addition, a mouthpiece 292 is fixedly mounted to the upper end ofpowder housing 228. Specifically, mouthpiece 292 has a cylindricalsecurement section 292k which is secured over the upper end of powderhousing 228 with a friction fit, a weld, an adhesive or the like.Cylindrical securement section 292k forms a chamber 292m which is influid communication with the upper end of venturi conduit 232. Afrusto-conical inhalation section 292n has its greater diameter endformed integrally with the upper end of cylindrical section 292k.Frustoconical inhalation section 292n has a central axial bore 292pformed entirely there through and which is in fluid communication withchamber 292m. In this manner, a user can inhale powder 234 throughventuri conduit 232, chamber 292m and bore 292p, when venturi conduits232 and 252 are in alignment with receptacle 224. The entire mouthpiece292 is preferably of a one-piece molded plastic construction.

A deflecting portion 292q of mouthpiece 292 includes a plurality of, forexample two, helical vanes 292r secured within bore 292p of inhalationsection 292n, in the manner taught in U.S. Pat. No. 4,907,583 toWetterlin. Helical vanes 292r deflect the powder particles so as to dashthe same against the inner wall of inhalation section 292p bycentrifugal force, whereby large particles or particle aggregates areshattered into small particles, and also, the particles collide witheach other which results in a mutual grinding or shattering actionbetween the particles.

The major difference between dispensers 110 and 210 is the manner inwhich disk portion 216 is rotated with respect to powder housing 228 andbase housing 248, which will now be described.

A first pin projection 296 is formed on the periphery of disk portion216, and extends radially outward therefrom. Preferably, pin projection296 is formed immediately above stop edge 214c of flange 214b. A secondpin projection 298 is formed on the periphery of base housing 248 nearthe lower end thereof, and extends radially outward therefrom to alength of approximately twice the radial length of first pin projection296. Second pin projection 298 is approximately 90° offset from firstpin projection 296 when stop pin 248c abuts either stop edge 214c or214d. Specifically, when stop pin 248c abuts stop edge 214d, second pinprojection 298 is in line with the center of flange 214b.

In order to engage pin projections 296 and 298 to rotate disk portion216 relative to powder housing 228 and base housing 248, a cylindricalguide sleeve 300 extends over the entire assembly so far described, thatis, sleeve 300 extends over base housing 248, stationary body 212 andmouthpiece 292. Guide sleeve 300 includes an axially oriented slot 302being open at the lower edge of guide sleeve 300 and extendingapproximately 76% of the height of guide sleeve 300. Slot 302 is adaptedto receive first pin projection 296. In this regard, the radial lengthof first pin projection 296 is such that the outer extent of first pinprojection 296 does not extend farther than the outside diameter ofguide sleeve 300. By this arrangement, guide sleeve 300 is effectivelylocked to disk portion 216 so that disk portion 216 is prevented fromrotating relative to guide sleeve 300, but is permitted to move axiallywith respect thereto, by means of first pin projection 296 in slot 302.

In addition, guide sleeve 300 includes a helical slot 304. Specifically,helical slot 304 includes an axially oriented lead-in portion 304a,which is open at the lower edge of guide sleeve 300 and extendsapproximately 10% of the height of guide sleeve 300. Lead-in portion304a is angularly offset from slot 302 by approximately 90°. Lead-inportion 304a leads into a helical portion 304b, which extends helicallyupward in a direction away from slot 302 to a position approximatelydiametrically opposite lead-in portion 304a and axially offset fromlead-in portion 304a. The juncture 304d of lead-in portion 304a andhelical portion 304b corresponds to the position of second pinprojection 298 therein when guide sleeve 300 is assembled over basehousing 248, stationary body 212 and mouthpiece 292. The height ofhelical portion 304b from its lead-in end to its termination end isapproximately 29% of the height of guide sleeve 300. Finally, helicalportion 304b terminates in a termination portion 304c which is orientedtransverse to lead-in portion 304a and which extends in a direction awayfrom helical portion 304b.

As an example of dimensions that can be used, guide sleeve 300 can havea height of 2.625 inches, axially oriented slot 302 can have a height of2 inches, lead-in portion 304a can have a height of 0.25 inch, andhelical portion 304b can have a height of 0.75 inch.

Helical slot 304 receives second pin projection 298 therein when guidesleeve 300 is inserted over base housing 248, stationary body 212 andmouthpiece 292. In this manner, if guide sleeve 300 is held stationary,rotation of second pin projection 298 will cause second pin projection298 to ride within helical portion 304b. As a result, base housing 248will rotate with respect to disk portion 216 which is held fixed byfirst pin projection 296 in slot 302 of guide sleeve 300. In thismanner, receptacle 224 will move from a position in alignment withmanifold 242 to a position in alignment with venturi conduits 232 and252 so that the user can inhale powder 234.

At the same time, it will be appreciated that movement of second pinprojection 296 will cause base housing 248 to move axially upward withrespect to guide sleeve 300. As a result, the entire arrangement of basehousing 248, stationary body 212 and mouthpiece 292 will move upwardly.Since slot 302 is axially oriented, disk portion 216 will still be fixedagainst rotation, but will move upwardly since first pin projection 296is positioned within slot 302. During this upward movement, mouthpiece292 will be rotated with base housing 248 and powder housing 228, andwill also be moved upwardly out of guide sleeve 300. In this regard,mouthpiece 292 will be exposed to the user when receptacle 224 is inalignment with venturi conduits 232 and 252. It will be appreciated thatsecond pin projection 298 seats within termination portion 304c at thisposition to maintain mouthpiece 292 in this extended position, until theuser provides a reverse rotation of second pin projection 298.

Guide sleeve 300 further includes a lower annular lip 306 extendingoutwardly therefrom, and slot 302 and lead-in portion 304a extendthrough lip 306.

In order to provide the aforementioned rotation of second pin projection298, a cylindrical driving sleeve 308 rotatably fits over a lowerportion of guide sleeve 300 and sits upon lower annular lip 306. Drivingsleeve 308 includes an axially oriented slot 310, open at the lower edgeof driving sleeve 308 and extending approximately the entire height ofdriving sleeve 300. For example, driving sleeve 308 can have a height of1.5 inches, with slot 310 having a height of 1.25 inches. In thisregard, driving sleeve 308 is slightly greater than one-half of theheight of guide sleeve 300. Slot 310 receives second pin projection 298when driving sleeve 308 is assembled on guide sleeve 300. Since theradial length of first pin projection 296 is such that the outer extentof first pin projection 296 does not extend farther than the outsidediameter of guide sleeve 300, first pin projection 296 will notinterfere with the rotation of driving sleeve 308 over guide sleeve 300.However, by this arrangement, driving sleeve 308 is connected withsecond pin projection 298 so that rotation of driving sleeve 308 willresult in rotation of second pin projection 298 within helical slot 306,while also permitting the aforementioned axial movement of second pinprojection 298.

A bottom friction cap 312 of the same height as driving sleeve 308 isfrictionally engaged over driving sleeve 308. Bottom friction cap 312performs a two-fold function. First, bottom friction cap 312 covers slot310 of driving sleeve 308 and second pin projection 298. Secondly,bottom friction cap 312 ensures a positive hold of second pin projection298 in slot 310, that is, bottom friction cap 312 prevents the sidewalls which define slot 310 from separating further by the force ofsecond pin projection 298 there against during the rotating forceapplied thereto. In this manner, when the user grasps and rotates bottomfriction cap 312, driving sleeve 308 which is frictionally engagedtherewith is also rotated, thereby functioning to rotate second pinprojection 298.

A top friction sleeve 314 is inserted over the remaining upper end ofguide sleeve 300, and is of the same diameter as driving sleeve 308. Topfriction sleeve 314 frictionally engages the upper end of guide sleeve300. In this manner, when the user grasps and rotates top frictionsleeve 314 relative to bottom friction cap 312, rotation of powderhousing 228 and base housing 248 occurs relative to disk portion 216, inthe manner previously discussed in detail.

Lastly, a cover cap 264 is removably inserted over top friction sleeve314 to cover the upper open end of mouthpiece 292 when not in use. Inorder to use dispenser 210, the user merely removes cover cap 264, androtates bottom friction cap 312 relative to top friction sleeve 314 toalign filled receptacle 224 with venturi conduits 232 and 252.

Dispenser 210 has the same advantages of dispenser 10, asaforementioned. In addition, as with dispenser 110, the mechanism forrotating powder housing 228 relative to metering disk 216 is associatedwith movement of mouthpiece 292 between its retracted and exposedpositions, and therefore provides a dual function in a simplifiedmanner.

Another embodiment of the powder dispenser of the present invention isnow explained with reference to FIG. 48, wherein elements correspondingto those of dispenser 210 of the third embodiment are denoted by thesame reference numbers, incremented by 100; a detailed description ofthe common elements will be omitted herein for the sake of brevity.

Dispenser 310 comprises, beginning at the lowermost portion of thedrawing, hollow cylindrical lower housing 500 provided with a flat uppertermination which functions as metering plate 316, the upper terminationbeing provided with a central opening 502 and a powder receptacleopening 324 near the periphery of the plate. Beneath the metering plateis a gas-permeable powder retainer 326; for reasons which will becomeapparent, only that portion of retainer 326 which lies directly beneathopening 324 must be gas-permeable but, for ease of fabrication, theentire retainer may comprise a gas-permeable material. Support 504 isdisposed beneath powder retainer 326 and is provided with a centralopening 506 and an opening 352 near the periphery which constitutes anair conduit. The support 504 is fixedly mounted to housing 500, suchthat the central openings of these components are aligned and opening324 will align with opening 352.

Powder housing 328 is cylindrical and generally closed, being providedwith a threaded opening in the lower portion thereof 507 for receivingbolt 558 and an opening 332 near the periphery which constitutes an airconduit. Contained within the powder housing is powder supply conduit336, filled with a desired amount of powder 334, and manifold 342 whichis constructed and performs substantially as previously described formanifolds 42 and 142. The powder housing may be provided with a lip 508,and the lower surface of the housing is biased against metering plate316 of lower housing 500 by spring 362, when bolt 558 is tightened.

Mouthpiece 392, which is constructed and functions similarly topreviously described mouthpiece 292, is attached to powder housing 328.Attachment may be accomplished by frictional or snap fit with lip 508 ofthe powder housing, alternatively by threaded engagement with the powderhousing, or by equivalent means, it being preferred to occasionallydetach the mouthpiece for cleaning.

It will be appreciated that the portion of dispenser 310 which is aboveline A--A is rotatable independently of the portion below the line. Forconvenience of operation, stop means (not shown) may be provided tolimit the angle of relative rotation. In operation, rotation is effectedto align powder receptacle 324 with manifold 342, whereupon thereceptacle becomes filled with powder 334; further rotation is effectedto align receptacle 324 with conduit 332, so that inhalation throughmouthpiece 392 will result in a measured dose of powder being entrainedin the inhaled air.

The embodiment shown in FIG. 48 has the advantage of a minimized numberof components, permitting ease of manufacture and a decreasedpossibility of equipment malfunction before the powder supply has beendepleted. Further enhancements may be provided without undulycomplicating the manufacturing process, such as providing a chamber inthe powder housing for holding a desiccating substance in vaporcommunication with the powder supply conduit; this may comprise anextension of powder supply conduit 336, which extension is filled withdesiccant 510 (such as silica gel) and provided with a vapor-permeableplug or membrane 512 to prevent contamination of the medicament powderwith desiccant. As in previously described embodiments, it may bedesirable to provide cover caps over the mouthpiece and/or the lowerhousing for hygienic reasons during periods of nonuse.

A further embodiment is shown in FIGS. 49-51, as an example of a devicewhich is readily fabricated using a minimum number of components, and iseasily assembled:

FIG. 49 is an exploded view of powder inhaler 600 depicting base unit610 having a plurality of optional knurls 612 around its lower exteriorand threads 618 around its upper exterior. Keyed opening 616 ispreferably centered about the central axis of the base unit andretaining ledge 614, adapted to receive a lower surface of spring means620 (shown as a wave spring), is disposed about an upper area of thebase unit.

Motoring plate 622 is seated in the interior of the base unit above thespring means, with lower projection 626 interacting with keyed opening616 of the base unit to ;ensure simultaneous rotation of the base unitand motoring plate. Powder receptacle 624 is located in the meteringplate, and is constructed as described for other embodiments of theinvention. An upper projection 628 is provided, centered about thecentral axis of the metering plate, and may comprise a solid post or alobate form, or any other desired shape.

Powder housing 630 is a generally hollow tubular shell having airopenings 632 at the lower edge and a ridge 634, which is adapted toprovide a snap fit into a suitable groove (not shown in this figure)inside a lower portion of base unit 610. Powder reservior 636 extendsover an upper inner portion of the powder housing and is provided withmanifold openings 638 at its lower termination which preferably is aflat surface, in contact with an upper surface of metering plate 622when the device is assembled. Inhalation conduit 640 is adjacent to, andcoextensive in length with, powder reservior 636; the design is suchthat relative rotation of base unit 610 and powder housing 630 canselectively align powder receptacle 624 with either manifold openings638 for filling with powder, or inhalation conduit 640 for dispensing apreviously metered powder dose. Central opening 642 may be provided forreceiving a desiccant material, and is located above recess 644 whichcan receive Upper projection 628 of metering plate 622, for propercomponent alignment. Plug means 646 is provided for closing powderreservior 636, and plugging means 648 is provided for closing opening642; permeable substances are preferably used to facilitate vaporcommunication between the powder reservoir and the central opening.Powder housing 630 is preferably provided with supplementary airopenings 650 to reduce the effort required for inhalation through thedevice.

Mouthpiece 652, having inhalation opening 654 in fluid communicationwith inhalation conduit 640, is attached to powder housing 630 by anydesired means. Preferably, the mouthpiece is detachable for cleaning.

Cover 656, of which only a lower portion is shown, has an internallythreaded lower area(threads not shown), which engages with threads 618of base unit 610 to enclose the device during periods of nonuse.

FIG. 50 is a cross-sectional view of the assembled, previouslydescribed, components, except that mouthpiece 652 is shown in a partialside view.

FIG. 51 is a top view, looking downward from line 51-51, with cover 656,mouthpiece 652, plug means 646 and plugging means 648 removed. This moreclearly shows manifold openings 638, located in the lower termination ofpowder reservoir 636.

For the convenience and safety of users, this device may alsoincorporate stop means for limiting relative rotation of base unit 610and powder housing 630 to a predetermined angle. Also, it may bedesirable to incorporate means for producing an audible signal such as a"click" sound at the rotational limits, so that a user will know whenrotation has been correctly accomplished. A further, frequentlydesirable safety feature is a counter or other indicating mechanism towarn the user of impending powder depletion.

If a desiccant is required to protect the medicament against moisturecontamination, the device must have a cap which prevents the entry ofmoisture between uses. Otherwise, desiccant capacity may be reachedbefore all doses contained within the device are dispensed.

All of the foregoing dispensers may be fabricated from readily availablematerials, such as plastics, metals and the like. Typically, the variouscomponents which do not require porosity or other special propertieswill be molded from one or more thermoplastic substances having thedesired rigidity and strength. In some embodiments, the componentcontaining the powder receptacle is relatively thin and, to maintain arequired degree of surface flatness, should be constructed from a lesseasily deformed substance such as a reinforced plastic, ceramic ormetal. Of course, materials selected must be chemically compatible withthe medication to be dispensed. For reasons of cost, a maximumutilization of plastics will be preferred where the device is intendedto be disposable with no, or only a limited number of, medicamentrefills after the initial charge has been dispensed.

Having described specific preferred embodiments of the invention withreference to the accompanying drawings, it will be appreciated that thepresent invention is not limited to those precise embodiments and thatvarious changes and modifications can be effected therein by one ofordinary skill in the art without departing from the scope or spirit ofthe invention as defined by the appended claims.

What is claimed is:
 1. A powder dispenser comprising:powder housingmeans holding a supply of powdered material to be dispensed, said powderhousing means including a first conduit extending therethrough indisplaced relation to said supply of powdered material; metering platemeans holding a metered amount of said powdered material, said meteringplate means including only a single receptacle area therein for holdingsaid metered amount of said powdered material, said metering plate meansbeing positioned below said supply of powdered material, and saidmetering plate means and said powder housing means being rotatable withrespect to each other so that said single receptacle area is adapted tobe in fluid communication selectively with said supply of powderedmaterial or said first conduit; base housing means disposed below saidmetering plate means and including a second conduit in alignment withsaid first conduit when said receptacle area is in alignment with saidfirst conduit; spring means for biasing said base housing means and saidpowder housing means toward each other; and mouthpiece means forenabling inhalation of said metered amount of powdered material fromsaid single receptacle area in said metering plate means through thefirst conduit in said powder housing means, said mouthpiece means beingin fluid communication with said first conduit.
 2. A powder dispenseraccording to claim 1, wherein said powder housing means has a generallycylindrical configuration with a central axis, and said first conduitextends substantially axially therethrough at a position radially offsetfrom said central axis and substantially parallel thereto.
 3. A powderdispenser according to claim 1, wherein said single receptacle area ofsaid metering plate means is formed by a plurality of perforations whichretain powder therein until said powder is dispensed.
 4. A powderdispenser according to claim 1, wherein said metering plate meanscomprises an upper termination of said base housing means.
 5. A powderdispenser according to claim 1, wherein said metering plate meanscomprises a gas-permeable material, and said single receptacle areacomprises a recess in said metering plate means.
 6. A powder dispenseraccording to claim 1, further including rotation limiting means forlimiting rotation of said powder housing means relative to said meteringdisk means to an incremental angle of rotation.
 7. A powder dispenseraccording to claim 1, further including rotational drive means forrotating said powder housing means with respect to said metering diskmeans so that said first conduit is in fluid communication with saidreceptacle area, in association with movement of said mouthpiece meansto an exposed position to enable inhalation therefrom.
 8. A powderdispenser according to claim 1, wherein said powder housing isbi-directionally rotatable with respect to said metering disk meansbetween a first position in which said single receptacle area is influid communication with said supply of powdered material and a secondposition in which said single receptacle area is in fluid communicationwith said first conduit.
 9. A powder dispenser according to claim 1,further including scraper means for scraping said powdered material intosaid single receptacle area during relative rotation of said meteringplate means and said powder housing means, said scraper means beingpositioned between said supply of powdered material and said meteringplate means.
 10. A powder dispenser according to claim 9, wherein saidscraper means includes a scraper plate having a plurality of holestherein, said scraper plate being interposed between said supply ofpowdered material and said single receptacle area.
 11. A powderdispenser according to claim 10, further including means for rotatablyfixing said scraper plate with said powder housing means.
 12. A powderdispenser according to claim 1, wherein said single receptacle area ofsaid metering plate means is formed by a gas-permeable filter, mesh orperforated plate element located at a lower portion of an openingprovided in said metering plate means, said element having a height lessthan the thickness of said metering plate means.
 13. A powder dispenseraccording to claim 1, wherein said single receptacle area of saidmetering plate means is formed by a gas-permeable filter, mesh orperforated plate element contacting a lower surface of said meteringplate means and covering an opening which defines said receptacle area.14. A powder dispenser according to claim 1, further includingcylindrical wall means for holding said metering plate means inrotatable relation to said powder housing means.
 15. A powder dispenseraccording to claim 14, further including securement means for rotatablyfixing said powder housing means with said base housing means, whilepermitting axial movement there between.
 16. A powder dispenseraccording to claim 1, further including moisture barrier means forpreventing moisture from exhalation from passing into the dispenserthrough the mouthpiece means.
 17. A powder dispenser according to claim16, wherein said moisture barrier means includes a flap pivotallymounted in said mouthpiece means only for opening movement duringinhalation.
 18. A powder dispenser assembly according to claim 1,wherein said powder housing means further includes a third conduittherein for holding said supply of powdered material.
 19. A powderdispenser according to claim 18, wherein said powder housing means has agenerally cylindrical configuration with a central axis, and said thirdconduit extends substantially axially therethrough at a positionradially offset from said central axis and substantially parallelthereto.
 20. A powder dispenser according to claim 18, wherein saidpowder housing means further includes manifold means for supplying thepowdered material from said third conduit to said single receptaclearea.
 21. A powder dispenser according to claim 20, further includingscraper means for scraping said powdered material into said singlereceptacle area during relative rotation of said metering plate meansand said powder housing means, said scraper means being positioned insaid manifold means.
 22. A powder dispenser according to claim 21,wherein said scraper means includes at least one scraper plate arrangedin said manifold means, each said scraper plate having a lower edgeextending as far as a lower surface of said powder housing means.